The possibility of fitting a gyro is not new, people have experimented with helicopter gyros on the rudder. This is definitely against the rules, and the model processing before an event is the place to discover if such equipment is being used. The original question was, should we have checks to ensure nobody uses a gyro or stabilization system? I thought that was what model processing was for.
In the very near future however, I see that all kinds of devices will be packed into receivers. We already have loggers, voltage regulators, sensors, bus-systems and now gyros. Who knows what's next? It will likely mean that we have to go out of our way to find "classic" receivers. For helicopters, the FAI class F3C is the classic class with mechanical stabilization (flybar) and F3N is for flybarless systems. They have 3-axis gyros. These gyros can pretty much fly the chopper for you, with panic-buttons that instantly returns the heli to a stable hover, regardless of what you were up to. Will we see a future 3D-aerobatic class, where gyros are allowed?
I digress, here's what we have to conform to at the present time- the current F3A aerobatic rules, from the 2013 FAI Sporting code:
Definition of a Radio Controlled Aerobatic Power Model Aircraft
A model aircraft, but not a helicopter, which is aerodynamically manoeuvred in attitude, direction, and
altitude by a pilot on the ground using radio control. Variable thrust direction of the propulsion device(s) is
not allowed.
........
Radio equipment shall be of the open loop type (ie no electronic feedback from the model aircraft to the
ground except for the stipulations in Volume ABR B.11.2). Auto-pilot control utilising inertia, gravity or any
type of terrestrial reference is prohibited. Automatic control sequencing (pre-programming) or automatic
control timing devices are prohibited.
Example:
Permitted:
1. Control rate devices that are manually switched by the pilot.
2. Any type of button or lever, switch, or dial control that is initiated or activated and terminated by the competitor.
3. Manually operated switches or programmable options to couple and mix control functions.
Not permitted:
1. Snap roll buttons with automatic timing mode.
2. Pre-programming devices to automatically perform a series of commands.
3. Auto-pilots or gyros for automatic wing levelling or other stabilisation of the model aircraft.
4. Automatic flight path guidance.
5. Propeller pitch change with automatic timing mode.
6. Any type of voice recognition system.
7. Conditions, switches, throttle curves, or any other mechanical or electronic device that will prevent
or limit sound level of the propulsion device during the sound/noise test.
8. Any type of learning function involving manoeuvre to manoeuvre or flight to flight analysis.
There's a reference to ABR, B.11.2, which is a separate document. It states:
A Spread Spectrum technology receiver that transmits information back to the pilot-operated transmitter,
is not considered to be a “device for the transmission of information from the model aircraft to the
competitor”, provided that the only information that is transmitted is for the safe operation of the model
aircraft.
At a glance, it seems contradictory, but it means that you can use a downlink from the aircraft for safety purposes. That to me includes current monitoring, but excludes GPS, such as speed and positioning data which would be a huge benefit (you'd get a vibration alert from the transmitter if you are more than 175 metres out, or pushing the sector limit, for instance).